OFFSET
0,6
COMMENTS
In terms of the repetition convolution operator #, where (sequence A) # (sequence B) = the sequence consisting of A(n) copies of B(n), then this sequence is the repetition convolution A110595 # n. Over the set of positive infinite integer sequences, # gives a nonassociative noncommutative groupoid (magma) with a left identity (A000012) but no right identity, where the left identity is also a right nullifier and idempotent. For any positive integer constant c, the sequence c*A000012 = (c,c,c,c,...) is also a right nullifier; for c = 1, this is A000012; for c = 3 this is A010701.
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..5000
FORMULA
G.f.: 1 + (1/(1 - x))*Sum_{k>=0} x^(5^k). - Ilya Gutkovskiy, Jan 08 2017
a(n) = floor(log_5(n)) + 1 for n >= 1. - Petros Hadjicostas, Dec 12 2019
MATHEMATICA
Join[{1}, IntegerLength[Range[110], 5]] (* Harvey P. Dale, Aug 03 2016 *)
CROSSREFS
KEYWORD
nonn,base,easy
AUTHOR
Jonathan Vos Post, Jul 29 2005
STATUS
approved